Analysis of test methods for texture depth evaluation applied in Portugal

Texture is a surface characteristic which has a very wide influence on pavements functional quality. It is currently assessed by a number of test methods. Road Administrations face the problems of dealing with data acquired by different methods and, in addition to that, the repeatability and reproducibility of the results. This paper presents an analysis of test methods used for texture depth evaluation in Portugal: the volumetric patch method and two methods based on surface profiles. Hence, three roads with low (dense asphalt), medium (“open texture asphalt”) and high (porous asphalt) texture depths were selected, where five profilometers made five runs. Two subsections of 150 m length were also selected to carry out the volumetric patch test. The texture indicators analysed were: the mean texture depth, the mean profile depth and the sensor measured texture depth. The average and the standard deviation were the statistical parameters used for the analysis. The results obtained for each method are significantly different and a good correlation between the mean profile depth and the sensor measured texture depth was established.